Improvement in hot-air furnaces



2 Sheets--Sheet 1.

- G. ILMJLLER. Hot-Air Furnaces.

Patented my 1, 1873.

UNITED STATES PATENT OFFICE.

GEORGE H. MILLER, OF LEAVENWORTH, KANSAS.

IMPROVEMENT IN HOT-AIR FURNACES.

Specification forming part of Letters Patent No. 140,523,4 dated July 1,1873; application led May 31, 1873.

To all whom it may concern:

Be it known that I, GEORGE H. MILLER, of Leavenworth, in the county ofLeavenworth and State of Kansas, have invented a new and valuableImprovement in Furnaces; and I do hereby declare that the following is afull, clear, and exact description of the construction and operation ofthe same, reference being had to the annexed drawings making a part ofthis specification, and to the lettersA and figures of reference markedthereon.

Figure l of the drawings is a plan view of my furnace. Fig. 2 is a sideelevation of the same. Fig. 3 is a sectional view. Fig. 4 is a detailview.

This invention has relation to furnaces for heating air; and it consistsin the construction and novel arrangement of the crucial radiator,having its arms extending horizontally and radiallyfrom the centerthereof, just above the highest portion of the fire-pot, dome, orcrown-sheet, and in connection therewith, of the oblique air-pipesthrough the arms of the radiator or drum, and the telescopic or tubulardamper, whereby the draft is not only regulated, but the heated productsof combustion, entering the arms of the drum near their outer ends, aremade to traverse every part vof each arm of the drum before ascendingthe smoke-pipe, rising from the center of said drum or radiator. Thisinvention also consists in the removable sliding basket-grate, and inconnection therewith ofthe rotary or dumping bottom-grate. 'And,finally, in the arrangement of the air-pipe at the rear of the fire-pot,connecting the cavity of the ash-pit, just under the grate, with thecavi-ty of the fire-pot just over the coal-bed, for the purpose ofrarefying the air for the consumption ofthe gas. The object of theseimprovements is to provide a domestic furnace of compact form andeconomical construction, efficient in action, and easily cleaned. Theradial construction of the radiator or drum is adapted to utilize thespace above the circular fire-pot, which is preferred in domestic use,in the most complete manner producing, with such a fire-pot, results atonce economical and satisfactory.'

In the accompanying drawings, the letterA designates a raised base orplatform, consisting of a circular rim, a, provided with thediametricall y crossing strengthening ribs b,

whose lower edges are designed usually to be' resting on the plate c,which is preferably flanged around its edge to form a sand-joint. To thewalls of the ash-pit are secured lugs or ledges d, for the flange e ofthe sliding basketgrate C to rest upon. The basket-grate is usuallyconstructed with the upright bars forming the side wall, said barsslanting a little outward. A circular opening is made in its base forthe reception ofthe dumping or bottom grate D, having anoperating-shaft, g, lsecured to it diametrically from front to rear, andextending forward out to the mouth of the ash-pit. This shaft g isjournaled at its inner end in the seat h, secured to the base of thebasket-grate, and at its outer end, near the mouth of the ash-pit, isprovided with a loose or separable bracket journal-seat, 7c, adapted toengage with the lugs or rests l of the ash-pit wall, in such a mannerthat its attachment to said wall will not interfere with its operationin drawing out the sliding basket-grate to the mouth ofthe ash-pit.Through the rear wall of the ash-pit an opening, m, is made, and anexternal hollow boss, n, attached to the outside of said wall forconnection with a section, p, of gas-pipe, designed to carry up warm airfrom the ash-pit into the lire-pot above the coal-bed, an opening, q,being made at this point through the Wall of the lire-pot, and ahollowboss, o, attached externally to said wall for connection with the upperend of the pipe-section p. Suitable flanges having been constructedaround the large opening above the grate, in the upper wall of theashpit, to form a sand-joint, the lower edge of the fire-pot wall E isarranged to rest therein, its

ripper edge being also suitably flanged at s, to form a sand-joint withthe edge ot' the dome or crown sheet F of the tire-pot. The dome is highand well arched. It is provided in front with a coal-chute, t, and withfour bent pipes, G, at the opposite ends of diameters crossing eachother at right angles, and near the base of the dome. The pipes Grextend outward and vertically upward, to support the arms or radialchambers H of the radiator, being connected to the under side of saidchambers near their outer ends. It is apparent that these pipes G areradially arranged with reference to the drum, although bent upward, asabove mentioned, until their outer ends are nearly or quite on a levelwith the summit of the dome, or sufficiently high to receive thecouplings of the radiator. K indicates the radiator, crucial in form,the arms or radial chambersH being horizontally extended outward fromthe central chamber L, which is located immediately above the summit ofthe dome, in such a manner that its axial line will coincide with thatof the fire-pot.- The radiator, in order that it may be light, and thuseasily supported by the radial conducting-tubes of the dome, ispreferably of sheet metal. The form of the radiator may be described astwo centrally and horizontally intersecting prisms of equal length, saidprisms being preferably octagonal and at right angles with each other.Therefore the arms or radial chambers H will have each two vertical andtwo horizontal walls and four oblique walls. Oblique air-tubes M passthrough each radial chamber H crosswise of each other, connecting,respectively, the upper and lower oblique walls u of opposite sides. Theincrease of radiatingsurface by means ot' these inner pipes is verynearly equal to the external prismatic surface. Although the circularform may be used in this radiator, the prismatic is preferred, as currents are created thereby in the rising heated air, in variousdirections, preventing, as it were, a thin sheet of heated air fromoccupying the radiating-surface continuously. With the same object inview, the joint flanges w of the radiator are constructed horizontallyalong the vertical walls fu. The currents of heated air ascending bythese radiating-walls c are thus broken. From the center of the upperwall of this central chamber L of the radiator rises the smoke-pipe P,provided with an internal sliding tube, N, extending downward into saidcentral chamber, and designed to be moved up or down by means of anoperating-rod, z, to regulate the passage of the heated products ofcombustion. The

cleaning-apertures, having suitable caps T. The end walls R should bemade with anges, so that they can be removed at intervals when a morethorough cleaning out of the drum is required.

This furnace is designed mainly for soft or bituminous coal, but willwork with hard coal equally well. Its operation is as follows Firehaving been kindled in the lire-pot, the gas therein formed is consumed,warm air from the ash-pit being introduced for this purpose into thefire-pot above the coal-bed. Gold-air currents, passing under, around,and about the fire-pot and ash-pit in the furnacechamber, become heated,and rise around the radiator, between its arms H, and through theoblique pipes M, thereby becoming rapidly heated for transmissionthrough suitable pipes from the furnace-chamber in the ordinary manner.The summit or hottest part of the dome, being immediately below themiddle of the chamber L, serves to reheat the products of combustion atthis point which have been conducted by the elbow-tubes G into the outerends of the radial chambers H. At the same time, the tubular damper Nhaving been adjusted downward, the currents of the products ofcombustion are carried over the oblique pipes and in contact with thewalls of the radiator, until, partially cooling, they descend toward thecenter ofthe chamber L, are reheated, and rise at once through thesliding tube and smoke-pipe.

The operating-rod of the sliding tube may be extended upward from thefurnace-chain ber into the dwelling portion of the house, where it maybe manipulated for the regulaB tion of the furnace-draft, the tube beingraised when the re is too low and let down when the heat is too great.

What I claim as my invention, and secure by Letters Patent, is-

l. A radiator having the radial chambers H and the central chamber Laxially arranged over the center of the fire-pot, substantially asspeciled.

2. The radiator, having air-tubes M passing through its radial chambersH, smoke-inlets at the ends of said chambers, the central verticalsmokeoutlet pipe, and the tubular damper dor extension tube,substantially as speci- 3. The combination, with a radiator having acentral smoke-pipe, of a lire-pot dome axially arranged below saidradiator and the desire to tubes G, connecting the base of said domewith the radial chambers-of said radiator, substantially as specified.

4. The combination, with a removable or sliding basket-grate and aconnected rotating or dumping grate, of the operating-rod and theremovable journal-seat bracket, substantially as specified.

5. The horizontallysliding or removable basket-grate and the removablerotating er dumping bottom grate journaled at the rear In testimony thatI claim the above I have of said basket-grate and at the front of thehereunto subscribed my naine in the presence ash-pit, substantially asspecified. of two witnesses.

6. The combination, with a radiator having chambers H, the centralchamber L, and a vertical smoke-pipe, of the vertical cylindricaldamper-tube sliding in said smokepipe, and long enough to extend to theoor of said radiator, substantially as specified.

GEO. H. MILLER.

Witnesses D. D. KANE, GEORGE E. UPHAM.

